ffzz
Responses from ffzz
| 300b lovers @lynn_olson Will you consider ultrapath capacitor as opposed to cathod bypass capacitor in self-bias? | |
| Not sure for power conditioner my amp or not. Since OP’s amp uses an EI power transformer which does isolation already, adding a separate isolation transformer may not give any benefit. However, if the isolation transformer is wired in balanced manner, then it can help. | |
| 300b lovers For DHTs such as 300B, AC at main frequency is hard to be hum free. But some have tried AC at a high frequency well above human hearing limit with decent result. Sadly this is mostly in DIY world, hence very few commercial offerings with high freq... | |
| 300b lovers 45 is indeed very very nice sounding. Cost has gone up quite a bit though. $2k will be barely enough these days for a high quality 45SET DIY project, assuming no fancy enclosures and not using big name irons like ISO or Hashimoto. ... | |
| 300b lovers @atmasphere I have to admit that the conclusion about SE+PP leads to emphasis on 5th harmonic is a bit counter-intuitive to me from pure math perspective, but I haven’t read his paper and perhaps there are certain situations that contribute to t... | |
| 300b lovers @lynn_olson I did check catalog of one European manufacturer for SE to PP interstage transformers. Within the limited offerings, it does seem that a tube with low Rp is needed in the SE stage - if not a DHT, ones like 6EM7 (the half with 750ohms... | |
| 300b lovers @lynn_olson How about using SE as opposed to PP in the first stage and a SE to PP interstage transformer between the first and second stage? | |
| 300b lovers Many roads lead to Rome... As to DHT shootout, using the same driver may suit certain output DHT tubes better than the other ones. Different DHTs also need different output transformers, different B+ voltages and filament supplies, etc. So AB tes... | |
| 300b lovers I prefer preamps with output transformers too. Luckily, there are decent line output transformers around that are not too expensive, certainly cheaper than exotic caps. But sadly preamps with output transformers are not often offered by preamp man... | |
| 300b lovers @charles1dad I belong to the camp that prefers simple triode circuit with interstage coupling in DHT SET. It sounds more dynamic and transparent to my ears. I don’t think it’s just an implementation issue though. DHT output tubes such as 300B a... | |
| 300b lovers @atmasphere The approach you described is used in DIY world for DHT SET, particularly 300B SET. There is a group who prefers this approach and there is a group who prefers the more simple way - using half or the 6SN7 in parallel as one triode an... | |
| 300b lovers @charles1dad My first tube amp was a Viva Solista Lt - a 845 SET with 6SN7 driver. The Viva Solista Lt produces more than 8 watts that many 300B amps advertise for, but only marginally more. I had the amp for 6-7 years. Out of curiosity, I trie... | |
| The 300B World Even in the case of capacitor coupling, loading the driver tube with a choke instead of a resistor will sound better - more dynamic and immediate sounding. No escape from good irons! SET amps are simple, yet there are many circuit design and part... | |
| The 300B World Properly designed power supply + well chosen operating point will lead to much less sensitivity to the choice of rectifier tube in SET. The flip side is such design often needs a lot of space: multiple chokes with decent inductance each as opposed... | |
| Need to build a headphone system For chamber music, small ensemble, and solo instrument, Sennheiser HD600 or its upper series with DHT SET (singled-ended design as opposed to push-pull) amp will be fantastic. I build my own tube amps as a hobby and use DHTs such as 71A, 45 with... |